You can’t see them, but this water is likely filled with nanoplastics. Photo: Unsplash
Nanoplastics are a scourge. They’re a tiny one, and one that’s easy to ignore because they’re so tiny, but they’re a scourge nonetheless. A new study from the Royal Netherlands Institute for Sea Research (NIOZ) and Utrecht University showed just how big of an issue they are: some 27 million tons of plastic are currently bobbing around in the North Atlantic Ocean.
Nanoplastics, which are smaller than the more frequently reported on microplastics, are usually defined as plastic particles smaller than one micrometer. Since microplastics are plastic particles smaller than five micrometer, nanoplastics are a subset of microplastics.
“Plastic pollution of the marine realm is widespread, with most scientific attention given to macroplastics and microplastics,” the authors of the study wrote in the journal Nature. “By contrast, ocean nanoplastics remain largely unquantified, leaving gaps in our understanding of the mass budget of this plastic size class.”
We’re only just beginning to understand the effects that the enormous amounts of plastic in our environment is having. Nanoplastics are thought to be small enough to get through tissues and cells of living creatures, which is obviously bad for a variety of reasons.
According to research from the National Institute of Health, “In vitro experiments with human cells and in vivo data generated with mice showed that microplastics elicit adverse health effects mainly by causing inflammation, oxidative stress [increased reactive oxygen species (ROS) production], lipid metabolism disturbances, gut microbiota dysbiosis, and neurotoxicity.”
Nanoplastics, as you may have guessed, are created when microplastics degrade even further than they already have. Chemical weathering mechanical breakdown, and even animal digestion can play a role, and nanoplastics are much too small to be seen with the naked eye. It’s not, however, a case of “out of sight, out of mind.”
They’re absolutely everywhere, and on a scale that seems insurmountable. In our blood, in our clouds, our seas, our soil. We’re creating more and more plastic every day, and most of it will be around for centuries after we’re all dead and gone. And the North Atlantic is a hotbed for nanoplastics in particular.
“There is more plastic in the form of nanoparticles floating in this part of the ocean than there is in larger microplastics or macroplastics floating in the Atlantic — or even across all the world’s oceans,” said Helge Niemann, a researcher at NIOZ and professor of geochemistry at Utrecht University.
Much of the plastic we create eventually winds up in the sea, despite how much of it we simply dump in landfills. This happens through a variety of methods.
“A substantial fraction of the global annual plastic production ends up in the ocean,” the study’s authors continued. “For example, through riverine transport, atmospheric deposition, and direct coastal or ship-based littering. The further fate of plastic debris in the ocean depends on several factors, including the density of the plastic items and their transport at the ocean surface. Accumulation hotspots of floating plastics include bays and convergence zones, such as the subtropical ocean gyres, and a considerable fraction of marine plastic litter is redeposited along shorelines.”
To figure out just how many nanoplastics were out there, researchers aboard the research vessel RV Pelagia sailed the North Atlantic from the subtropical gyre to the northern European shelf, collecting water from a dozen different locations along the way. They then filtered out particles larger than one micrometer, which is not the easiest thing to do.
“By drying and heating the remaining material,” explained Utrecht University master’s student Sophie ten Hietbrink, who was in on the study, “we were able to measure the characteristic molecules of different types of plastics in the Utrecht laboratory, using mass spectrometry.”
This appears to be the first time the amount of nanoplastics has been quantified in a meaningful way, and the result is pretty horrifying.
“A shocking amount,” ten Hietbrink said. “But with this, we do have an important answer to the paradox of the missing plastic.” The “missing plastic paradox” refers to the discrepancy between the amount of plastic produced and discarded (which is massive), and the relatively small amount found in the ocean.
